Key frame construction for pianos and like musical instruments

ABSTRACT

A front rail constituting a key frame for supporting the keys of a piano comprises a plurality of rectangular wooden blocks connected end to end to form an elongated rail body, and a surface covering member of synthetic resin material securely attached to at least the entire upper surface of the rail body. The surface covering member serves to protect the rail body from being affected by the humidity conditions, so that the front rail is subjected to less warping deformation. Other surfaces of the rail body may also be covered by the surface covering member so as to completely prevent moisture from causing the front rail to be warped.

United States Patent 11 1 Yamada Nov. 27, 1973 KEY FRAME CONSTRUCTION FOR PIANOS' AND LIKE MUSICAL INSTRUMENTS I TSI WEIWE K oichi viinaaa, flarnain atsu,

Japan [73] Assignee: Nippon GakkiSeizo Kabushiki Kaisha, Shizuoka-ken, Japan 22 Filed July 12,1971

21 Appl.No.:1 61,774

[30] Foreign Application Priority Data Aug. 28, 1970 Japan 45/852224 52 US. Cl. 84/423, 84/433 51 Int. Cl Gl0c 3/12 [58] Fieldof Search 84/423, 430, 432, 84/433,434, 435, 436

' [56] References Cited 1 UNITED STATES PATENTS 2,466,511 4/1949 Swanson 84/434 3,561,315 2/1971 011116 84/433 3,499,362 3/1970 Harada 84/434 w ll! 12 1941 Fam 84/433 3,456,545 7/1969 Kondo 84/435 Primary ExaminerRichard B. Wilkinson Assistant Examiner-John F. Gonzales Attorney-Curt M.-Avery et al.

[57 9 ABSTRACT A front rail constituting a key frame for supporting the keys of a piano comprises a plurality of rectangular wooden blocks connected end to end to form an elongated rail body, and a surface covering member of synthetic resin material securely attached to at least the entire upper surface of the rail body. The surface covering member serves to protect the rail body from being affected by the humidity conditions, so that the front rail is subjected to less warping deformation.

Other surfaces of the rail body may also be covered by the surface covering member so as to completely prevent moisture from causing the front rail to be warped.

4 Claims, 2 Drawing Figures PATENTEUNUVN ma 3774.493

lNVE NTOR Komhi. Yam dw LIKE MUSICAL INSTRUMENTS DETAILED DESCRIPTION OFTI-IE INVENTION This invention relatesto a key frame forsupporting the keys of a-piano or the like musical instruments, and

.KEY FRAME CONSTRUCTION FOR PIANOS AND more particularly to a key frame construction comprising a rail member which is free from warping deformation as would be caused by variations in the moisture l0.

' pivoted on a key bed or board mounted on the piano case or frame. Each key is fulcrumed ona balance rail of akey frame supported'on' the key .bedfThe 'blance rail is disposed between front andrearfrail members in spaced relationship therewith and connected thereto by asuitable number of transverse members or" slats.

The inner end of each key is limited in its lowermost position by a felt pad or stop provided on the rear rail member while the outer end is in alignment with the front face of the front rail member. It has been the conventioal practice to form the front It isanother object of the invention to provide a key frame of the type mentioned above and which key frame is simple in construction, easy to manufacture and capable of maintaining the pin members securely anchored therein. a

According to one feature of the invention, a key frame for a piano or like musical instruments including front and'balance rail members spaced apart from each other and supporting a plurality of keys thereon, at

least one of the rail members comprisinga plurality of wooden blocks connected end to end to form an elongated rail body, and a surface covering member of syn- .with the surface thetic resin material securely attached to the rail body. According to another feature ofthe invnetion, that surface of the rail body facing the keys may be covered covering member of synthetic resin material. 1

and intermediate balance rails of the key frame from v wood material. However, wood has a disadvantage that it is susceptible'toinfluences ofmoistrue contents in the surrounding atmosphere. The conventional, key frame has a body'structures of its front, balancev and rear rail members formed from a-sigle piece of wood and therefore is easily deformed when there occur variations in theenvironmental moisture conditions. The warping deformation of the key frame, especially of the front rail member, causes irregular positional displacements to the keys supported thereon with the result that, the keys cannot be maintained in uniformly spaced relationship on a horizontal plane. Furthermore, the irregular positional displacement of the keys must be prevented strictly since they wouldotherwise be caused to lose balance duringlpivoting movements thereof. It

is considered that the warp curving of the front, balance, or rear rail member is caused essentially by a differ ence in moisture content between the upper surface portion of the rail body structure and the lower surface portion which is closely in contact with a supporting bed or board. i

In order to avoid the warp curving, the front or balance rail member may be formed entirely from a synthetic resin material which has no or less moisture absorbing property. However, with a synthetic resin front or balance rail construction, it will be made difficult to securely anchor and retain the front or balance pin members therein. Furthermore, the synthetic resin material is not suitable for forming key frame rails as it has too much rigidity and would not congruously fit on the wood board member on which the key frame is supported.

This invention therefore contemplates to provide an improved key frame constructionwhich will eliminate the above difiiculties.

. According to stillanother feature of the invention, the opposite surface. of the rail'memb'er to that facing the keys may be covered with the surface member of synthetic resin material.

The above and other objects, features andattending v advantages of the invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate by way of example of one preferred embodiment of the invention, and wherein: I

' FIG. 1 is a schematic side view of the key frame construction according to the present inventiomand FIG. 2 is a fragmentary perspecive view showing, on an enlarged scale and in more detail, the front rail body structure and the manner in which the front pins are supported-on the front rail.

Before explaining the present invention in detail, it is tov be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various different ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of .description only and not of limitation.

Referring to the drawings, a more detailed description of the instant invention will be given. FIG. 1 shows in side elevation a piano key frame construction embodying the present invention and generally indicated by reference numeral 1. The key frame construction includes, same as in the conventional counterparts, a front rail member 4 and a rear rail member 6 disposed in parallel spaced relationship with the front rail memher 4. interposed between the front rail member 4 and the rear rail member 6 is an intermediate or balance rail member 5 havingbalance pin members 9 securely anchored therein. The front rail member 4, intermediate or balance rail member 5 and rear rail member 6 are" connected together by transversely extending slat member of which only the endmost one is shown at 3 with a capstan screw 15.

According to the invention, the front rail member 4 with front pin members 8 on the upper surface has an elongated body structure 12 consisting of a plurality of (usually 4 through 10) rectanglular wood piece or block members 11 of a same thickness connected end to end and sandwitched securely between two rlatively thin plate members 13 and 14 each formed from synthetic resin material such as acrylonitirle-butadienestyrene resin material. The plate or surface covering members 13' and 14 are applied coextensively to the upper and lower surfaces of the front rail bodystructure 12 with use of a suitable adhesive agent or compound. The synthetic resin plate member 13 is preferred to have a thickness'from one to two millimeters so as to facilitate passage therethrough of the front pin members 8. The front pin members 8 are securely ancho'red into and retained in the wood block members 11 at the respective root end portions which are passed through the upper covering plate member 13 .When

block members 11 are orientated such that their grains run in the longitudinal direction of or along the length of the'body structure 12.

With the front rail construction as described above, the upper surfaceof the front rail body structure 12 is covered with the synthetic resin material 13 so that there will be little or no possibility of the front rail member 4 being warped as'a result of moisture absorption through the upper surface portion of the front rail body structure 12; It is important tonote thateven if the'individual wood block members 11 are subjected to warping deformation, deformation of the front rail member as a whole may be much less than the conventional counterparts where the front rail body structure is formed from a single piece of wood. In addition to the resistance to deformation, the front rail construction of theinvention has a moderate rigidity so that it congruously fits on the board or bed on which the key forming the front rail body structure 12, the wood frame is supported. The synthetic resin plate member 13 covering the upper surface of the front rail body structure 12 is made thin enough to allow the front pin members 8 to be planted easily therethrough securely into the underlying wood block members 11. It will be appreciated from the foregoing that according to the invention the key misalignment or displacement which has been experienced due to warp curving of the front rail member may be compeltely avoided and the front pin members may be securely held in position.

In the embodiment described above, the front rail member 4 is shown as having both the upper and lower surfaces thereof covered with synthetic resin material 13 and 14. However, the lower surface of the front rail body structure 12 may not necessarily be provided with the covering plate member 14 since the lower surface is held in close contact with the supporting board or bed 2 and thus less influenced by environmntal moisture conditions. On the other hand, in order to eradicate the moisture influence on the front rail member 4 completely, the front or outer and the rear or inner faces of the front rail 4 may also be covered by the surface covering members of synthetic resin material in a like manner asexplained above, in addition to the upper and lower surfaces thereof. Needless to say, the intermediate balancerail S'and the rear rail 6 may be constructed in a manner similar to the front rail in order to achieve the same warp preventing effects.

What is claimed is:

1. In a key frame for a piano or like musical instruments, including front and balance rail members spaced apart from each other and supporting aplurality of keys thereon, at least one of said rail members comprising a plurality of wooden blocks connected end to end to form an elongated rail body having a keysupporting surface and another surface opposite to said key-supporting surface, said key-supporting surface facing said keys, a surface covering member of synthetic, resin material directly attached to said keysupporting surface, said surface covering member covering the entire area of said key-supporting surface, another surface covering member of synthetic resin material. directly attached to said other surface, said other surface coveringmember covering the entire area of said other surface. I

2. In a key frame for a piano or like musical instruments, including front and balance rail members spaced apart from each other and supporting a plurality of keys thereon, at least one of said rail members comprising an elongated rail body of wood having a keysupporting surface and another surface opposite to said key-supporting surface, said key-supporting surface facing said keys, a surface covering member of synthetic resin material directly attached to said keysupporting surface, said surface covering member covering the entire area of said key-supporting surface, another surface covering member of synthetic resin material directly attached to said other surface, said other surface covering member covering the entire area of said other surface. a 

1. In a key frame for a piano or like musical instruments, including front and balance rail members spaced apart from each other and supporting a plurality of keys thereon, at least one of said rail members comprising a plurality of wooden blocks connected end to end to form an elongated rail body having a keysupporting surface and another surface opposite to said keysupporting surface, said key-supporting surface facing said keys, a surface covering member of synthetic resin material directly attached to said key-supporting surface, said surface covering member covering the entire area of said key-supporting surface, another surface covering member of synthetic resin material directly attached to said other surFace, said other surface covering member covering the entire area of said other surface.
 2. In a key frame for a piano or like musical instruments, including front and balance rail members spaced apart from each other and supporting a plurality of keys thereon, at least one of said rail members comprising an elongated rail body of wood having a key-supporting surface and another surface opposite to said key-supporting surface, said key-supporting surface facing said keys, a surface covering member of synthetic resin material directly attached to said key-supporting surface, said surface covering member covering the entire area of said key-supporting surface, another surface covering member of synthetic resin material directly attached to said other surface, said other surface covering member covering the entire area of said other surface.
 3. In a key frame according to claim 1, wherein said surface covering members of synthetic resin material provide a rigidified sandwich construction with said wooden rail body while preventing moisture penetration therethrough to said intermediate wooden rail body to preclude warping of the latter.
 4. In a key frame according to claim 2, wherein said surface covering members of synthetic resin material provide a rigidified sandwich construction with said wooden rail body while preventing moisture penetration therethrough to said intermediate wooden rail body to preclude warping of the latter. 